Centralized radio access network (C-RAN), also called as cloud-RAN, is a network constructed by a plurality of distributed remote radio heads (RRHs). C-RAN utilizes the virtualization technique incorporates with the wire network to centralize the baseband resource. This technique leads to a revolution on the architecture and design of the baseband unit. The connection and algorithm of the baseband unit and the radio head are therefore changing so as to efficiently share the resources to implement the loading balance and error tolerance in network. The C-RAN can simplify the back haul but increase the complexity of the connections between the baseband unit and the plurality of remote radio heads, the front haul.
Please refer to FIG. 1, which is a schematic of a C-RAN. As shown in FIG. 1, a C-RAN 1000 has a baseband unit BBU and a plurality of remote radio heads RRH01˜RRH20 corresponding to the baseband unit BBU, and there is also a user end device UE moving in the region where the remote radio heads RRH01˜RRH20 are located. The physical locations of the remote radio heads RRH01˜RRH20 are different from one another. The baseband unit BBU is communicatively connected to the remote radio heads RRH01˜RRH20. Explicitly, there is data packets sent/received between the baseband unit BBU and any one of the remote radio heads RRH01˜RRH20.
In the conventional C-RAN, when the baseband unit BBU needs to send a packet to the user end device UE, the baseband unit BBU sends the packet to all of the remote radio heads RRH01˜RRH20 when all RRHs are belong to the same cell, so the network traffic between the baseband unit BBU and the remote radio heads RRH01˜RRH20 is occupied by a large number of packets.